This invention relates to axially restrained pipe joints.
One well known form of pipe joint, for example, comprises a bell end provided on one pipe, an interfitting spigot end on an attached pipe, and a sealing gasket interposed between the bell and spigot ends. Numerous locking arrangements have been proposed for use in such joints to prevent axial movement of the spigot end relative to the bell end. Thus, for example, one such locking arrangement employs a split snap ring located inside of the bell end and which can be adjusted radially by a ring adjustment mechanism between a relaxed condition allowing for axial movement of the respective pipe ends and a tightened position in which the ring engages a circumferential bead or the like on one of the pipe ends to preclude relative axial movement therebetween in a direction separating the pipes. One particular form of snap ring structure of this type is shown, for example, in prior U.S. Pat. No. 4,428,604 to Conner and which is commonly assigned herewith. In the patented device, the adjustment mechanism for the snap ring comprises transverse pieces which extend axially from the respective ends of the split snap ring out of the mouth of the bell end, radial lugs on the outer ends of the transverse pieces, and a threaded stud connecting the lugs whereby radial adjustment of the segmented ring within the bell end as between the relaxed and tightened conditions is effected externally of the bell end by rotating the threaded stud nuts in the appropriate direction.
While pipe joints of the general type referred to above are in extensive use and are generally regarded as being satisfactory in performance, the present invention seeks to improve the design thereof in certain respects, more particularly in regard to the locking ring structure, so as to provide, inter alia, improved joint performance and characteristics.